EP1617372B1 - Dispositif d'imagerie, procédé de commande afférent, et logiciel - Google Patents

Dispositif d'imagerie, procédé de commande afférent, et logiciel Download PDF

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EP1617372B1
EP1617372B1 EP05015369A EP05015369A EP1617372B1 EP 1617372 B1 EP1617372 B1 EP 1617372B1 EP 05015369 A EP05015369 A EP 05015369A EP 05015369 A EP05015369 A EP 05015369A EP 1617372 B1 EP1617372 B1 EP 1617372B1
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image data
reduced
radiation
external device
imaging unit
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EP1617372A1 (fr
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Hideki Nonaka
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Canon Inc
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Canon Inc
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06TIMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T3/00Geometric image transformation in the plane of the image
    • G06T3/40Scaling the whole image or part thereof

Definitions

  • the present invention relates to an imaging apparatus which outputs, to an external device, image data obtained by an imaging unit to radiograph a subject by using radiation, a control method thereof, and a program.
  • radiography In normal X-ray imaging, radiography is executed by a film screen system or an IP (Imaging Plate) system using photostimulable phosphor. It takes several minutes to see a sensed image. This is because a time is necessary for a film process in the former system and for reading by a reading apparatus in the latter system.
  • IP Imaging Plate
  • the radiographed state i.e., whether exposure in radiography was appropriate or whether the target was radiographed at an accurate angle is confirmed after such a wait time. For this reason, if radiography fails, the workflow of X-ray inspection may be disturbed.
  • Japanese Patent Laid-Open No. 2002-186606 discloses an X-ray diagnosis apparatus operation method which executes various kinds of correction for data obtained by undersampling a whole image and then displays the data by using a solid-state detector for X-ray image display.
  • the pixel matrix of a general digital X-ray imaging apparatus includes several thousand x several thousand pixels (e.g., 2,000 x 2,000 pixels or more). Since data per pixel is 8 to 16 bits, an enormous data amount must be transferred. To shorten the time until preview display under these circumstances, the data transfer rate must be increased by using a multi-bit data transfer path or increasing the data transmission rate.
  • Image data cannot be used as a diagnostic image until it undergoes preprocesses such as offset correction, gain correction, and defect correction and post-processes such as dynamic range adjustment and display LUT adjustment.
  • parameters for image adjustment change depending on the type (e.g., target part) of a sensed image.
  • the parameters for the post-processes must be determined by analyzing the sensed image.
  • a preview image can be used for this analysis, the processing speed of the system can be increased.
  • a high-quality preview image is necessary.
  • the image quality is insufficient in an uncorrected coarse image or a simple offset correction image using dummy offset data obtained by pre-calibration.
  • the characteristics of the parts of the imaging unit change depending on the environment such as ambient temperature. Dark noise in the X-ray detector in the imaging unit varies even depending on the radiographic operation time. Calibration data cannot contain these variation components before radiography. To minimize the variation components, offset data must be acquired by reproducing the same operation as in radiography in an X-ray non-irradiation state immediately after radiography.
  • the present invention has been made to solve the above-described problems, and has as its object to provide an imaging apparatus capable of rapidly and efficiently outputting the preview image of a sensed image, a control method thereof, and a program.
  • an imaging apparatus which outputs, to an external device, image data obtained by an imaging unit to radiograph a subject by using radiation, comprising:
  • the reduction means generates the reduced image data by extracting, from all pixels obtained by the imaging unit, at least one of pixel groups located on two pairs of diagonals of an n x n pixel (n: natural number) square region of the imaging unit.
  • the value n is determined on the basis of at least one of necessary size and image quality of the reduced image data, a time allowable for output to the external device, a pixel pitch of the imaging unit, and a grid pitch of an X-ray antiscatter grid.
  • the reduction means generates one pixel of the reduced image data, which expresses an n x n pixel (n: natural number) square region on all pixels, by extracting, from all pixels obtained by the imaging unit, at least one of pixel groups located on two pairs of diagonals of the n x n pixel square region of the imaging unit and executing a filter operation for the extracted pixels.
  • the value n is an even number
  • a weight is an even function
  • the output means first outputs the reduced radiation image data to the external device at once, then outputs the reduced reference image data to the external device at once, and finally outputs the offset-corrected radiation image data obtained by the execution means to the external device.
  • the output means first divides the reduced radiation image data into a predetermined division unit and sequentially outputs the data to the external device, then divides the reduced reference image data into a predetermined division unit and sequentially outputs the data to the external device, and finally outputs the offset-corrected radiation image data obtained by the execution means to the external device.
  • the second storage means stores the reference image data obtained by the imaging unit in the radiation non-irradiation state after the radiation image data obtained by the imaging unit in the radiation irradiation state is stored in the first storage means.
  • the reduction means first generates the reduced radiation image data substantially simultaneously with storage of the radiation image data in the first storage means, the output means outputs the reduced radiation image data to the external device, the reduction means then generates the reduced reference image data substantially simultaneously with storage of the reference image data in the second storage means, and the output means then outputs the reduced reference image data to the external device and finally outputs the offset-corrected radiation image data to the external device.
  • the foregoing object is attained by providing a control method of an imaging apparatus which outputs, to an external device, image data obtained by an imaging unit to radiograph a subject by using radiation, comprising:
  • the foregoing object is attained by providing a program which implements control of an imaging apparatus which outputs, to an external device, image data obtained by an imaging unit to radiograph a subject by using radiation, comprising:
  • Fig. 1 is a block diagram showing the arrangement of an X-ray imaging apparatus according to the embodiment of the present invention.
  • An imaging unit 1 is connected to a controller 2 serving as an external device through an external communication cable 20.
  • the controller 2 provides a diagnostic image by executing preprocesses such as offset correction, gain correction, and defect correction and post-processes such as dynamic range adjustment and display LUT adjustment for image data received from the imaging unit 1 and also controls the imaging unit 1.
  • the controller 2 is formed from a general-purpose computer such as a personal computer.
  • the general-purpose computer has constituent elements such as a CPU, RAM, ROM, hard disk, external storage device, network interface, display, keyboard, and mouse.
  • image output devices such as a monitor and printer may be connected to the imaging unit 1 as external devices.
  • the imaging unit 1 includes units shown in Fig. 1 .
  • Reference numeral 3 denotes a flat panel detector (to be referred to as an FPD hereinafter).
  • the FPD 3 is formed by combining a scintillator made of, e.g., cesium iodide (CsI) and a two-dimensional photodetector made of amorphous silicon (a-Si).
  • CsI cesium iodide
  • a-Si amorphous silicon
  • the imaging unit 1 by X-ray imaging will be exemplified.
  • the present invention can also be applied to radiation other than X-rays.
  • the pixels on each row of the two-dimensional photodetector are addressed simultaneously by an FPD driving circuit 6.
  • the outputs are held by sample-and-hold circuits 7.
  • the held pixel outputs pass through a multiplexer (MUX) 8.
  • the charge is amplified by an amplifier (AMP) 9 and sequentially converted into a digital value by an A/D converter 10.
  • the read operation or imaging operation is controlled by an FPD control circuit 5.
  • the FPD driving circuit 6 sequentially drives the rows on the FPD 3.
  • the values of all pixels of the FPD 3 are converted into digital values by the A/D conversion operation of the A/D converter 10.
  • the output from the A/D converter 10 is stored in a first frame memory 13 or second frame memory 14 through a first FIFO 11 and frame memory bus arbitration circuit 12.
  • the frame memory bus arbitration circuit 12 is provided to write data from the FPD 3 and execute bus arbitration of the data read from a CPU 4.
  • the frame memory bus arbitration circuit 12 also has a function of a bus selector which selects a frame memory to write data from the FPD 3 in the X-ray irradiation state and non-irradiation state.
  • a bus selector which selects a frame memory to write data from the FPD 3 in the X-ray irradiation state and non-irradiation state.
  • the data is written in the first frame memory 13.
  • the data is written in the second frame memory 14.
  • the same data is sent to a sampling circuit 15.
  • the sampling circuit 15 sends only necessary data to a second FIFO 16 of the subsequent stage such that a predetermined sampling pattern is obtained.
  • an offset image as a correction image (reference image) to correct the variation components is acquired by reproducing the same operation as in radiography in the X-ray non-irradiation state immediately after radiography.
  • offset correction processing is executed between the offset image and the X-ray image obtained by X-ray imaging, an offset-corrected X-ray image whose variation components are corrected can be obtained.
  • X-rays When passing through a subject, X-rays cause scattering in addition to absorption by the subject itself. An X-ray image is observed through a subject by using the X-ray source as a light source. Hence, only X-ray components which have passed through the subject in a straight line from the X-ray source are preferably detected. Scattered X-rays are scattered even to portions except lines which connect the X-ray source and the pixels on the FPD 3. Such an image is fogged and blurred as a whole.
  • an X-ray antiscatter grid which contains a substance with a high X-ray absorbance and a substance with a low X-ray absorbance (e.g., a combination of lead and aluminum) in a grid shape is arranged between the subject and the imaging unit 1. Only X-ray components which enter from the projection line from the X-ray source are made to pass through the pixels on the FPD 3. Other X-ray components are absorbed by the high X-ray absorption substance. With this arrangement, an image with a high contrast is obtained.
  • the substance itself which forms the matrix of the X-ray antiscatter grid, also has a thickness.
  • the intensity distribution of X-rays which pass through the X-ray antiscatter grid is generated in accordance with the period of the grid array (to be referred to as a grid pitch hereinafter).
  • Sampling is executed for the periodical signal by the pixels on the FPD 3.
  • moire (to be referred to as grid fringes herein) is generated on the acquired image in accordance with both the grid pitch and the pixel pitch.
  • the pixel size in the imaging unit 1 is 160 ⁇ m x 160 ⁇ m.
  • the grid pitch of the X-ray antiscatter grid is 40 grids/cm. To check only grid fringes, no subject is placed. An X-ray image corresponding to only the X-ray antiscatter grid is acquired at a low tube voltage. As a reduced image, an image with an area ratio of 1/8 is assumed. One pixel of a reduced image is formed from an 8 x 8 pixel region. Pixels as shown in Fig. 2 are extracted, and the simple mean values of the pixels are used (these modes will be defined as 4-point mean and 8-point mean, respectively, hereinafter).
  • the size of the square region including n x n pixels is determined on the basis of at least one of the necessary size and quality of the reduced image (one pixel of a reduced image expresses a wider region as n becomes large so that the image becomes coarse), the time allowable for reduced image transfer, the pixel pitch of the imaging unit 1, the grid pitch of the X-ray antiscatter grid, and the grid fringe generation period predicted from the pixel pitch and grid pitch.
  • Fig. 3 shows the mean power spectrum of the entire image in the horizontal direction.
  • the spectrum of the entire image and the mean power spectra of the two types of reduced images are superimposed.
  • the grid fringes are not completely suppressed in the reduced image by 4-point mean.
  • the filter characteristic of the 4-point mean reduced image is given by Z - 1 + Z - 2 + Z - 3 + Z - 4 4
  • the filter characteristic of the 8-point mean reduced image is given by Z - 1 + Z - 2 + Z - 3 + Z - 4 + Z - 5 + Z - 6 + Z - 7 + Z - 8 8
  • Z is the delay operator (z transform) corresponding to one sample (160 ⁇ m); since it is the horizontal spectrum characteristic that is important, this can be considered by projection of a two-dimensional weight coefficient).
  • Z is the delay operator (z transform) corresponding to one sample (160 ⁇ m); since it is the horizontal spectrum characteristic that is important, this can be considered by projection of a two-dimensional weight coefficient).
  • 4-point mean an image with a lower degree of suppression in the low-frequency region, i.e., an image without blur at a higher resolution can be obtained.
  • 8-point mean is more advantageous.
  • the resolution is insufficient in the simple mean.
  • a filter coefficient must be set. With the pixel pitch and grid pitch assumed here, grid fringes are generated near 2.25 cyc/mm. For this reason, a filter whose degree of suppression is high in this region and low in the low-frequency portion is suitable.
  • the weight of each point is an even function (pairs of four points).
  • the degree of suppression is high in a high-frequency region of 1.5 cyc/mm or more.
  • the same characteristic as in 4-point mean is ensured in a region of 1.5 cyc/mm or less where image components are mainly contained. Since a smooth characteristic is obtained, no inverted point (zero point) is present.
  • a filter 0-1-4-8-8-4-1-0 is applied to eight diagonal pixels in an 8 x 8 pixel region to form one pixel of a reduced image.
  • the positions of pixels to be extracted and the filter are point-symmetrical with respect to the center of the 8 x 8 pixel region. Hence, no problem is posed.
  • At least one of pixel groups located on the diagonals of the 8 x 8 pixel region is extracted to form a reduced image. Even when another pixel group on the diagonals is extracted to form a reduced image, the same effect as described above can be obtained.
  • the reduced image creation method is determined on the basis of the reduction ratio of the reduced image with respect to the entire image, the pixel pitch of the imaging unit, and the grid pitch of the X-ray antiscatter grid.
  • the numerical values used here are merely examples, and the present invention is not limited to this.
  • the filter represented by expression (3) is given by k 1 ⁇ Z - 1 + k 2 ⁇ Z - 2 + ... + k n / 2 ⁇ Z - n / 2 + k n / 2 ⁇ Z - n / 2 + 1 + ... + k 2 ⁇ Z - n - 1 + k 1 ⁇ Z - n 2 ⁇ k 1 + k 2 + ... + k n / 2 - 1 + k n / 2 / 2 / 2 / 2 k 1 + k 2 + ... + k n / 2 - 1 + k n / 2 / 2 / 2 / 2
  • the imaging unit 1 may execute only extraction of diagonal pixels in the 8 x 8 pixel region.
  • the extracted data is transferred to the controller 2 so that the subsequent filter processing is executed by the controller 2.
  • the data transfer amount can be reduced to 1/8 of the entire image data. Hence, the purpose of shortening the time until preview display can be achieved.
  • the sampling method can easily be implemented by counting the number of pixels in the main scanning direction and the number of lines in the sub-scanning direction. For example, to extract the above-described pixels on the diagonals of the 8 x 8 pixel region, 3-bit cyclic counters are used. In the main scanning direction, the count value is incremented every time one pixel of the FPD 3 is read. In the sub-scanning direction, the count value is incremented every time one line of the FPD 3 is read.
  • the count range is 0 to 7. The value returns from 7 to 0.
  • F the count values
  • the filter processing can also easily be implemented.
  • a coefficient to be multiplied is selected from the value of the counter F in the main scanning direction.
  • the actual operation is implemented by a shift operation.
  • the count value of the counter F using the same coefficient is the same when the exclusive OR of bit 0 or 1 and bit 2 is calculated.
  • the division in the filter operation represented by expression (3) can be implemented by hardware including a comparator, adder (subtraction processing can be executed by adding a complement of 2 of the numerical value to be subtracted), and shift operator if the simplest integral operation can be employed.
  • the filter operation is done for the 8 x 8 pixel region, as described above.
  • the data read from the FPD 3 is executed for each line. For this reason, sampling pixel data selected in accordance with the above-described sampling method must be held until the read of eight lines is ended.
  • a memory which has a storage capacity equal to or more than the image data size of eight lines and holds sampling pixel data is prepared separately.
  • the above-described filter coefficient multiplication, addition of sampling pixel data after coefficient multiplication, and division processing are executed for the sampling pixel data stored in the memory. Then, the data is output to the second FIFO 16.
  • a memory which has a capacity equal to or more than the data size of (pixels of one line/8) pixels and holds sampling pixel data is prepared separately.
  • filter coefficient multiplication and addition of sampling pixel data after coefficient multiplication are executed.
  • An operation result for a sampling pixel in the same 8 x 8 pixel region is written back to the same memory area.
  • the division processing is executed in addition to the above-described filter coefficient multiplication and sampling pixel data addition, and the operation result is written back to the memory.
  • the memory When the read of eight lines is ended, a result obtained by executing the filter operation for sampling pixels in the 8 x 8 pixel region is held by the memory.
  • the data may sequentially be transferred to the second FIFO 16.
  • the memory may be formed from a dual port memory to replace the second FIFO 16.
  • Fig. 6 shows the operation main flow of the X-ray imaging apparatus according to the embodiment of the present invention.
  • Figs. 7A and 7B show the sub-flow which is executed in parallel to the operation main flow when sampling pixel data (reduced image data) is stored in the second FIFO 16.
  • Figs. 8 and 9 are timing charts showing the X-ray output, FPD driving state, and data communication state along the time axis plotted along the abscissa.
  • the FPD 3 is in the initialization state.
  • the FPD 3 switches for the initialization state to the imaging state (step S101).
  • the X-ray irradiation state may always be monitored, and the imaging state may be set upon detecting X-ray irradiation.
  • the driving state of the FPD 3 and the X-ray irradiation state may be synchronized by causing the controller 2 or imaging unit 1 to establish synchronization with respect to the X-ray control device (controller 2).
  • the controller 2 or imaging unit 1 may establish synchronization with respect to the X-ray control device (controller 2).
  • any method can be used.
  • X-ray irradiation is executed (step S102).
  • the end of X-ray irradiation is determined (step S103).
  • FPD 3 charges corresponding to the intensity of incident X-rays are generated and accumulated.
  • an imaging time t is stored (step S104).
  • the FPD 3 switches to the read state (step S105).
  • the read method has been described above. This will briefly be described below.
  • One pixel is read from the FPD 3 (step S106). It is determined whether the read pixel is a sampling target pixel (step S107). If the pixel is a sampling target pixel (YES in step S107), the flow advances to step S108 to store the pixel data of the read pixel in the second FIFO 16. Then, the flow advances to step S109 to store the pixel data of the read pixel in the first frame memory 13. If the pixel is no sampling target pixel (NO in step S107), the flow advances to step S109 to store the pixel data of the read pixel in the first frame memory 13.
  • step S110 It is determined whether all pixels on the FPD 3 are read (step S110). If the read is not ended (NO in step S110), the flow returns to step S106. If the read is ended (YES in step S110), the flow advances to step S111.
  • a full-size X-ray image of the subject is stored in the first frame memory 13, and the sampling X-ray image (reduced X-ray image) is stored in the second FIFO 16.
  • the FPD 3 switches to the initialization state (step S111). Then, the FPD 3 switches to the imaging state (step S112). After switching to the imaging state, it is determined whether the stored imaging time t has elapsed (step S113). If the imaging time t has elapsed (YES in step S113), the FPD 3 switches to the read state (step S114).
  • One pixel is read from the FPD 3 (step S115). It is determined whether the read pixel is a sampling target pixel (step S116). If the pixel is a sampling target pixel (YES in step S116), the flow advances to step S117 to store the pixel data of the read pixel in the second FIFO 16. Then, the flow advances to step S118 to store the pixel data of the read pixel in the second frame memory 14. If the pixel is no sampling target pixel (NO in step S116), the flow advances to step S118 to store the pixel data of the read pixel in the second frame memory 14.
  • step S119 It is determined whether all pixels on the FPD 3 are read (step S119). If the read is not ended (NO in step S119), the flow returns to step S115. If the read is ended (YES in step S119), the flow advances to step S120.
  • a full-size offset image in the X-ray non-irradiation state is stored in the second frame memory 14, and the sampling offset image (reduced offset image) is stored in the second FIFO 16.
  • a subtraction circuit 21 executes offset correction by using the X-ray image stored in the first frame memory 13 and the offset image stored in the second frame memory 14.
  • the offset-corrected full image is output to the controller 2 through a CPU bus interface circuit 22, CPU bus, data communication circuit 19, and external communication cable 20.
  • the reduced X-ray image and reduced offset image sequentially stored in the second FIFO 16 are sequentially transferred to the controller 2.
  • Fig. 7A shows the process flow of outputting the reduced image at once.
  • step S201 It is determined whether data (reduced image data) stored in the second FIFO 16 is present (step S201). If no data is present (NO in step S201), the flow advances to step S203. If data is present (YES in step S201), the flow advances to step S202 to cause a DMA interface circuit 17 to transfer, through the CPU bus, the data stored in the second FIFO 16 to a DMA buffer region set on a main memory 18.
  • step S203 It is determined whether DMA transfer of all data of the reduced image data is ended (step S203). If DMA transfer is not ended (NO in step S203), the flow returns to step S201. If DMA transfer is ended (YES in step S203), the flow advances to step S204 to convert the reduced image data stored in the DMA buffer region on the main memory 18 into a data format to be output through the data communication circuit 19. Then, the data is transferred to the data communication circuit 19 and output to the controller 2 through the external communication cable 20.
  • the reduced image data in Fig. 7A corresponds to the reduced X-ray image and reduced offset image obtained by the processing in Fig. 6 .
  • Fig. 8 is a timing chart showing the operation of outputting the reduced image at once.
  • Fig. 7B shows the process flow of divisionally outputting the reduced image.
  • step S211 It is determined whether data (reduced image data) stored in the second FIFO 16 is present (step S211). If no data is present (NO in step S211), the flow advances to step S215. If data is present (YES in step S211), the flow advances to step S212 to cause the DMA interface circuit 17 to transfer, through the CPU bus, the data stored in the second FIFO 16 to the DMA buffer region set on the main memory 18.
  • step S213 It is determined whether DMA transfer of the reduced image data for one cycle of divisional transfer is ended (step S213). If DMA transfer is not ended (NO in step S213), the flow advances to step S215. If DMA transfer is ended (YES in step S213), the flow advances to step S214 to convert the divided reduced image data for divisional transfer, which is stored in the DMA buffer region on the main memory 18, into a data format to be output through the data communication circuit 19. Then, the data is transferred to the data communication circuit 19 and output to the controller 2 through the external communication cable 20.
  • step S215 It is determined whether output of all reduced image data to the controller 2 is ended (step S215). If output is not ended (NO in step S215), the flow returns to step S211. If output is ended (YES in step S215), the processing is ended.
  • the reduced image data in Fig. 7B corresponds to the reduced X-ray image and reduced offset image obtained by the processing in Fig. 6 .
  • Fig. 9 is a timing chart showing the operation of divisionally outputting the reduced image.
  • a full-size X-ray image is stored in the first frame memory 13, and a sampling X-ray image is transferred to the controller 2.
  • a full-size offset image is stored in the second frame memory 14, and a sampling offset image is transferred to the controller 2.
  • the CPU 4 transfers the full image data stored in the first frame memory 13 and second frame memory 14 to the data communication circuit 19. If bus access from the CPU 4 occurs, the full image data (whole image data) are read out from the two frame memories.
  • the subtraction circuit 21 calculates and outputs the difference between the two data. With this processing, offset-corrected full reduced image is transferred.
  • the DMA interface circuit 17 has a function of a so-called DMA controller (DMAC) and functions as a bus master.
  • DMAC DMA controller
  • the present invention is not limited to this.
  • a DMAC may separately be prepared on the CPU bus. If the CPU 4 incorporates a DMAC, the DMAC may be used, and the DMA interface circuit 17 may generate a DMA transfer request signal to the DMAC. The same effect as described above can be obtained even when DMA transfer itself is done by the DMAC or DMAC incorporated in the CPU.
  • DMA transfer need not always be executed.
  • the same effect as described can be obtained even when the DMA interface circuit 17 is replaced with a data transfer request signal generation circuit for the CPU 4, and data transfer is executed by the CPU 4.
  • the CPU 4 transfers the full image data stored in the first frame memory 13 and second frame memory 14 to the data communication circuit 19. If bus access from the CPU 4 occurs, the full image data (whole image data) are read out from the two frame memories.
  • the subtraction circuit 21 calculates and outputs the difference between the two data. With this processing, offset-corrected full reduced image is transferred.
  • a preview image can immediately be displayed without increasing the speed of the data output path.
  • the quality of the obtained preview image can be maintained high.
  • a result obtained by analyzing the preview image can be used for determining image adjustment parameters of post-processes. Hence, the processing speed of the system can be increased.
  • the embodiment has been described above in detail.
  • the present invention can take an embodiment such as a system, apparatus, method, program, or storage medium. More specifically, the present invention can be applied to a system including a plurality of devices, or to an apparatus including a single device.
  • the present invention is also achieved even by supplying a software program (in the embodiment, a program corresponding to the flowcharts shown in the drawings) which implements the function of the above-described embodiment to the system or apparatus directly or from a remote site and causing the computer of the system or apparatus to read out and execute the supplied program code.
  • a software program in the embodiment, a program corresponding to the flowcharts shown in the drawings
  • the program code itself which is installed in the computer, also implements the present invention. That is, a computer program itself, which implements the functional processing of the present invention, is also incorporated in the claim of the present invention.
  • the program can take any form such as an object code, a program to be executed by an interpreter, or script data to be supplied to the OS as long as the functions of the program can be obtained.
  • a recording medium to supply the program for example, a floppy (registered trademark) disk, hard disk, optical disk, magnetooptical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, or DVD (DVD-ROM or DVD-R) can be used.
  • a client computer may be connected to a homepage on the Internet by using a browser in the computer, and the computer program itself of the present invention or a compressed file containing an automatic install function may be downloaded from the homepage to a recording medium such as a hard disk.
  • a program code that constitutes the program of the present invention may be divided into a plurality of files, and the files may be downloaded from different homepages. That is, a WWW server which causes a plurality of users to download a program file that causes a computer to implement the functional processing of the present invention is also incorporated in the claim of the present invention.
  • the program of the present invention may be encrypted, stored in a storage medium such as a CD-ROM, and distributed to users. Any user who satisfies predetermined conditions may be allowed to download key information for decryption from a homepage through the Internet, execute the encrypted program using the key information, and install the program in the computer.
  • the function of the above-described,embodiment is also implemented when the program read out from the storage medium is written in the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer, and the CPU of the function expansion board or function expansion unit performs part or all of actual processing on the basis of the instructions of the program.

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Claims (11)

  1. Appareil d'imagerie qui délivre en sortie, à un dispositif extérieur (2), des données d'image obtenues par une unité d'imagerie (1) pour radiographier un sujet en utilisant un rayonnement, comportant :
    un premier moyen de stockage (13) destiné à stocker des données d'image de rayonnement obtenues par l'unité d'imagerie (1) dans un état d'irradiation d'un rayonnement ;
    un second moyen de stockage (14) destiné à stocker des données d'image de référence obtenues par l'unité d'imagerie (1) dans un état de non irradiation de rayonnement ;
    un moyen de réduction (16) destiné à générer des données d'image de rayonnement réduite et des données d'image de référence réduite en tant que données d'image réduite des données d'image de rayonnement et des données d'image de référence ;
    un moyen d'exécution (21) destiné à exécuter un traitement de correction de décalage entre les données d'image de rayonnement et les données d'image de référence ; et
    un moyen de sortie (19) destiné, après la fin de la sortie des données d'image de rayonnement réduite et des données d'image de référence réduite vers le dispositif extérieur (2), à délivrer en sortie au dispositif extérieur des données d'image de rayonnement corrigées en décalage, obtenues par ledit moyen d'exécution (21).
  2. Appareil selon la revendication 1, dans lequel ledit moyen de réduction (16) génère les données d'image réduite en extrayant, de tous les pixels obtenus par l'unité d'imagerie (1), au moins l'un de groupes de pixels se trouvant sur deux paires de diagonales d'une région carrée de n x n pixels (n : nombre naturel) de l'unité d'imagerie.
  3. Appareil selon la revendication 2, dans lequel la valeur n est déterminée sur la base d'au moins l'une d'une taille nécessaire et d'une qualité d'image des données d'image réduite, d'un temps admissible pour la sortie vers le dispositif extérieur, d'un pas de pixels de l'unité d'imagerie et d'un pas de grille d'une grille anti-dispersion de rayons X.
  4. Appareil selon la revendication 1, dans lequel ledit moyen de réduction (16) génère un pixel des données d'image réduite, qui exprime une région carrée de n x n pixels (n : nombre naturel) sur tous les pixels, en extrayant, de tous les pixels obtenus par l'unité d'imagerie (1), au moins l'un de groupes de pixels se trouvant sur deux paires de diagonales de la région carrée de n x n pixels de l'unité d'imagerie et en exécutant une opération de filtrage sur les pixels extraits.
  5. Appareil selon la revendication 4, dans lequel, dans l'opération de filtrage, la valeur n est un nombre pair, et un coefficient de pondération est une fonction paire.
  6. Appareil selon la revendication 1, dans lequel ledit moyen de sortie (19) délivre d'abord en sortie en une seule fois au dispositif extérieur (2) les données d'image de rayonnement réduite, puis délivre ensuite en une seule fois au dispositif extérieur (2) les données d'image de référence réduite, et finalement délivre en sortie au dispositif extérieur (2), les données d'image de rayonnement corrigées en décalage obtenues par ledit moyen d'exécution (19).
  7. Appareil selon la revendication 1, dans lequel ledit moyen de sortie (19) divise d'abord les données d'image de rayonnement réduite en une unité de division prédéterminée et délivre séquentiellement en sortie les données au dispositif extérieur (2), puis divise les données d'image de référence réduite en une unité de division prédéterminée et délivre séquentiellement en sortie les données au dispositif extérieur (2), et délivre finalement en sortie au dispositif extérieur (2) les données d'image de rayonnement corrigées en décalage obtenues par ledit moyen d'exécution.
  8. Appareil selon la revendication 1, dans lequel ledit second moyen de stockage (14) stocke les données d'image de référence obtenues par l'unité d'imagerie (1) dans l'état de non irradiation de rayonnement après que les données de rayonnement obtenues par l'unité d'imagerie (1) dans l'état d'irradiation de rayonnement ont été stockées dans ledit premier moyen de stockage (13).
  9. Appareil selon la revendication 1, dans lequel ledit moyen de réduction (16) génère d'abord les données d'image de rayonnement réduite sensiblement simultanément au stockage des données d'image de rayonnement dans ledit premier moyen de stockage (13), ledit moyen de sortie (19) délivre en sortie les données d'image de rayonnement réduite au dispositif extérieur (2), ledit moyen de réduction (16) génère ensuite les données d'image de référence réduite sensiblement simultanément au stockage des données d'image de référence dans ledit second moyen de stockage (14), et ledit moyen de sortie (19) délivre ensuite en sortie les données d'image de référence réduite au dispositif extérieur (2) et délivre finalement en sortie les données d'image de rayonnement corrigées en décalage au dispositif extérieur (2).
  10. Procédé de commande d'un appareil d'imagerie (1) qui délivre en sortie, à un dispositif extérieur (2), des données d'image obtenues par une unité d'imagerie (1) pour radiographier un sujet en utilisant un rayonnement, comprenant :
    une première étape de stockage consistant à stocker des données d'image de rayonnement obtenues par l'unité d'imagerie (1) dans un état d'irradiation de rayonnement dans une première unité de stockage (13) ;
    une seconde étape de stockage consistant à stocker des données d'image de référence obtenues par l'unité d'imagerie (1) dans un état de non irradiation de rayonnement dans une seconde unité de stockage (14) ;
    une étape de réduction consistant à générer des données d'image de rayonnement réduite et des données d'image de référence réduite en tant que données d'image réduite des données d'image de rayonnement et des données d'image de référence ;
    une étape d'exécution consistant à exécuter un traitement de correction de décalage entre les données d'image de rayonnement et les données d'image de référence ; et
    une étape de sortie consistant, après la fin de la sortie des données d'image de rayonnement réduite et des données d'image de référence réduite vers le dispositif extérieur (2), à délivrer en sortie au dispositif extérieur (2) des données d'image de rayonnement corrigées en décalage obtenues dans l'étape d'exécution.
  11. Programme qui exécute une commande d'un appareil d'imagerie (1) qui délivre en sortie, à un dispositif extérieur (2), des données d'image obtenues par une unité d'imagerie (1) pour radiographier un sujet en utilisant un rayonnement, comportant :
    un code de programme pour une première étape de stockage consistant à stocker des données de rayonnement obtenues par l'unité d'imagerie (1) dans un état d'irradiation de rayonnement dans une première unité de stockage (13) ;
    un code de programme pour une seconde étape de stockage consistant à stocker des données d'image de référence obtenues par l'unité d'imagerie (1) dans un état de non irradiation de rayonnement dans une seconde unité de stockage (14) ;
    un code de programme pour une étape de réduction consistant à générer des données d'image de rayonnement réduite et des données d'image de référence réduite en tant que données d'images réduites des données d'image de rayonnement et des données d'image de référence ;
    un code de programme pour une étape d'exécution consistant à exécuter un traitement de correction de décalage entre les données d'image de rayonnement et les données d'image de référence ; et
    un code de programme pour une étape de sortie consistant, après la fin de la sortie vers le dispositif extérieur (2) des données d'image de rayonnement réduite et des données d'image de référence réduite, à délivrer en sortie au dispositif extérieur (2) des données d'image de rayonnement corrigées en décalage obtenues dans l'étape d'exécution.
EP05015369A 2004-07-15 2005-07-14 Dispositif d'imagerie, procédé de commande afférent, et logiciel Expired - Fee Related EP1617372B1 (fr)

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US7639857B2 (en) 2009-12-29
US20060013465A1 (en) 2006-01-19
JP4546174B2 (ja) 2010-09-15
JP2006026083A (ja) 2006-02-02
DE602005013856D1 (de) 2009-05-28

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